For industrial and construction purposes bulk materials of natural or artificial origin, are excavated or obtained from recycling. These bulk materials are typically loaded into “cargo bodies” or “loading bodies” or “loading platforms” or “open containers” on transport means to be delivered, with or without intermediate storage (and associated additional loads), after one or more treatments (for making them “suited”) at a place of use in an industrial or civil engineering application.
An efficient and qualitative process should ensure maximum added value with guarantees for all stakeholders and with minimal adverse side effects, including for the environment. In particular, the CO2 efficiency needs to be examined as well as maximum recycling to reduce dumping of waste materials as well as the exploitation of primary raw materials.
For construction purposes, for example as regards infrastructure works, delivery of construction materials (e.g. mixtures of mineral materials with lime and/or cement, foundation materials, materials for enveloping, backfill, embankment, drainage, etc.) at the right time, at the right place are contemplated.
Treatment of soil (making it suited by improving its properties) may be necessary for reasons of purification (sanitation), stabilization, consolidation or strengthening.
It is important that the quality of the works carried out by the contractor, especially for mentioned treatments, can be controlled and assured. It should be possible to comply with various requirements such as engineering and environmental requirements, and monitoring and control thereof should also be possible.
The ‘making suited’ of soil for engineering purposes is done mainly by intensive mixing of the soil with other soil and mineral flows and with additives. The additives mainly relate to cement, (quick) lime and other agents.
On-site stabilization works (in combination with earth works, embankments, foundations, etc.) for train paths, highways, main roads, etc. traditionally involve the spread out of cement and/or (quick) lime on the subsurface (consisting of soil and/or granulates, whether added or not), followed by an intensive mixing in layers of up to 60 cm in thickness, by means of milling, with or without addition of water. The processed whole is leveled and compacted so as to form a stable base for the superstructures to be realized. Excavation, transportation, replacement and disposal of waste soil are hardly required. Typically large quantities are involved in these applications.
In smaller-scale applications as well as in sewerage works, cohesive soil needs to be dug out, excavated, transported and, in order to make it suitable for reuse, collected in a separate area, spread and mixed with additives, scraped and again put on stock to be reloaded and transported back eventually as small loads to the construction site for use as a building material in foundations, envelops, backfilling. Quality control is almost impossible in these circumstances because of the heterogeneous nature of the underground, the moisture and the composition, the uncertainty of the precise quantity of applied milled additives. Often large displacements are required, which also implies logistical problems. A separate area is needed that is suitable for the mentioned intensive activities of unloading, spreading, milling, stocking up, loading, transportation, etc.
A solution for improving excavated soil in smaller scale projects would be the treatment of the soil, at the location of the excavation. However, this is time-consuming if done by means of the excavator as little or no other work can be performed during this soil improvement. Furthermore, in case of local treatment, near to the location of the excavation, the various machines needed here for are often standing in the way. Moreover, the activity of improving the soil may give rise to dust, which is disturbing and harmful for humans and for the environment.
Thus, there remains a need for an efficient system, and an efficient method for the improvement (making suited) of excavated soil.